Many Japanese verbs are designed in pairs: one intransitive (自動詞), one transitive (他動詞). They share the same root but have different endings. Learn one pair and you've mastered both "something happens on its own" and "someone makes it happen."
Core Comparison Table
| Intransitive (が) | Transitive (を) | Meaning |
|---|---|---|
| 開く (あく) | 開ける (あける) | open |
| 直る (なおる) | 直す (なおす) | get fixed / fix |
| 流れる (ながれる) | 流す (ながす) | flow / play (music) |
| 見つかる (みつかる) | 見つける (みつける) | be found / find |
| 残る (のこる) | 残す (のこす) | remain / leave behind |
| 倒れる (たおれる) | 倒す (たおす) | fall over / knock down |
| 集まる (あつまる) | 集める (あつめる) | gather / collect |
| 立つ (たつ) | 立てる (たてる) | stand / set upright |
| 始まる (はじまる) | 始める (はじめる) | begin (itself) / start (something) |
Pair-by-Pair Breakdown
開く / 開ける (open)
ドアが開いている。 → The door is open. (Intransitive: the door's state)
弟がドアを開ける。 → My brother opens the door. (Transitive: someone acts)
To say "please open the door," you must use the transitive verb: ドアを開けてください。
The intransitive 開く takes a thing (the door) as its subject, so it can't take てください — you can't request a door to open itself.
直る / 直す (get fixed / fix)
自転車が直った。 → The bicycle got fixed. (Intransitive: result state)
弟が自転車を直す。 → My brother fixes the bicycle. (Transitive: someone repairs it)
風邪が治った。 → The cold got better. (Intransitive: natural recovery)
Note: The kanji 「直す」 means to repair objects, while 「治す」 means to treat illness — but both are read なおす. Their intransitive counterparts are 「直る」 (get repaired) and 「治る」 (recover), both read なおる.
流れる / 流す (flow / play)
このレストランでは音楽が流れている。 → Music is playing in this restaurant. (Intransitive: no one is specifically mentioned)
音楽を流す。 → Play music. (Transitive: someone plays it)
No specific person mentioned → intransitive; someone deliberately does it → transitive.
見つかる / 見つける (be found / find)
財布が見つかった。 → The wallet was found. (Intransitive: the wallet's state)
いいアパートを見つけたいんです。 → I want to find a good apartment. (Transitive: someone searches)
"The wallet was found" — English uses passive voice, but Japanese uses an intransitive verb because the focus is on the wallet's state.
残る / 残す (remain / leave behind)
ここにたくさんの自転車が残っている。 → A lot of bicycles remain here. (Intransitive: natural state)
良い作品を残そう。 → Let's leave behind good work. (Transitive: someone deliberately leaves it)
The same concept of "leaving behind" — Japanese distinguishes between a natural state and a deliberate action.
倒れる / 倒す (fall over / knock down)
山田さんが倒れた。 → Yamada collapsed. (Intransitive: fell on their own)
山田さんが田中さんを倒す。 → Yamada knocks down Tanaka. (Transitive: someone acts)
あの会社が倒れた。 → That company went bankrupt. (Intransitive: thing as subject)
Notice: 山田さんが倒れた (Yamada fell) vs. 山田さんが倒す (Yamada knocks someone down). Same subject, different verb, completely different meaning.
集まる / 集める (gather / collect)
ゴミが集まっている。 → Trash has accumulated. (Intransitive: natural gathering)
ここにゴミを集めてください。 → Please collect the trash here. (Transitive: requesting someone to collect)
A Common Trap: Look-Alike Forms
Some paired verbs have a potential form that looks identical to the other verb in the pair:
| Intransitive | Transitive | Transitive Potential Form |
|---|---|---|
| 立てる (たてる)? | 立てる (たてる) | 立てられる |
| 開く (あく) | 開ける (あける) | 開けられる |
The potential form of 立つ is 立てる — identical to the transitive verb 立てる! How to tell them apart? Check the particle:
椅子が立てる → Unnatural (a chair having ability?)
椅子を立てる → Set the chair upright (transitive)
See を → it's transitive. See が + person + 立てる → it's the potential form.
How to Memorize These Pairs
Honestly, there's no shortcut — accumulate them two by two over time. But one rule helps you quickly identify them:
- Ends in す → almost certainly transitive (流す, 直す, 倒す, 残す)
- Ends in まる → almost certainly intransitive (集まる, 始まる, 見つかる)
Summary
- Paired intransitive/transitive verbs are a hallmark of Japanese — learning them in pairs is most efficient
- Intransitive → subject takes が, describes states/natural occurrences
- Transitive → object takes を, describes someone's actions
- Ends in す → transitive; ends in まる → intransitive
- Don't confuse potential forms with the paired verb — check the particle
Practice Questions
Q1. Fill in the particles: 「自転車＿＿直った」and「弟＿＿自転車＿＿直す」
Answer
- 自転車が直った。 (Intransitive 直る → thing as subject → が)
- 弟が自転車を直す。 (Transitive 直す → brother is subject が, bicycle is object を)
Q2. How do you say "the wallet was found" in Japanese? 見つける or 見つかる?
Answer
Use 見つかる (intransitive): 財布が見つかった。 The wallet (thing) is the subject, describing its state → intransitive.
To say "I found the wallet" (someone's action), use 見つける: 財布を見つけた。
Q3. 「ゴミ＿＿集まっている」and「ここにゴミ＿＿集めてください」— what goes in the blanks?
Answer
- ゴミが集まっている。 (Intransitive 集まる → thing as subject → が)
- ここにゴミを集めてください。 (Transitive 集める → object takes を)